3 Meat Pizza Casserole

So I haven't actually made this yet. Someone posted it on Facebook and I thought it sounded good so I put it here so I would be able to find it again easily when I have all the ingredients to make it. It seems like it would make more than just a 9x13 pan. I'm sure you could cut back on some of the ingredients.

Ingredients
1 lb bow tie pasta
1 lb mild pork sausage
1 large onion, medium size chopped
2 (26 ounce) jars spaghetti sauce (I used Bertolli’s Mushroom and Garlic)
1 lb cubed cooked ham
1/2-1 lb of sliced pepperoni
3 (8 ounce) bags of shredded mozzarella cheese
6 tablespoons of grated parmesan cheese
2 tablespoons chopped garlic
1 teaspoon dried oregano　

Directions
1. Cook pasta in boiling water until al dent 
2. Cook sausage, garlic powder and oregano with onions until the juices run clear.
3. In a lightly greased 9x13x3 inch pan, pour a small amount of sauce to lightly coat bottom.
4. Layer ingredients in the order listed below.
5. 1st layer-1/3 of the pasta, 1/3 remaining sauce, 1 bag of mozzarella cheese, 2 Tablespoons parmesan cheese, sausage and onions.
6. 2nd layer-1/2 of the remaining pasta, 1/2 remaining sauce, 1 bag of mozzarella cheese, 2 Tablespoons parmesan cheese, ham.
7. 3rd layer-all remaining pasta, all remaining sauce, 1 bag of mozzarella cheese, 2 Tablespoons parmesan cheese, all the pepperoni(completely covering the entire top with pepperoni).
8. Bake at 375°F for 40 minutes.
9. Let sit for 5 minutes before serving.